Formed plate tube spacer structure

ABSTRACT

Antivibration tube spacer structure for supportingly spacing adjacent tubes of a shell and tube heat exchanger in order to prevent damage to the tubes caused by flow-induced or other mechanically induced vibration. The spacer structure comprises elongated, thin plate members disposed between adjacent tube layers thus to provide engagement at two opposed points on the tubes. Struck out tab projections extending normally from the plate are arranged to engage the tubes on opposite, longitudinally-spaced points that are displaced by 90* from the points of plate engagement.

United States atent [72] Inventor Nicholas D. Romanos Chattanooga, Tenn.[21] Appl. No. 849,701 [22] Filed Aug. 13, 1969 [45] Patented Apr. 20,1971 [73] Assignee Combustion Engineering, inc.

Windsor, Conn.

[54] FORMED PLATE TUBE SPACER STRUCTURE 26 Claims, 23 Drawing Figs.

[52] US. Cl 1.65/162, 122/510 [51] int. Cl F281) 9/00 [50] Field ofSearch 165/69, 178; 122/34; 122/510; 165/162 [56] References CitedUNITED STATES PATENTS 2,001,663 5/1935 Carlson 165/162 2,175,555 10/1939Brown 122/510 3,199,582 8/1965 Vogt et al. 165/69 3,292,691 12/1966Welter et al. l65/69X 3,420,297 l/l969 Romanos '165/162 3,503,440 3/1970Romanos. 165/162 3,509,939 5/1970 Weber 165/162 PrimaryExaminer-Frederick L. Matteson Assistant ExaminerTheophi| W. StreuleAttorneys-Carlton F. Bryant, Eldon H. Luther, Robert L. Olson, John F.Carney, Richard H. Berneike, Edward L. Kochey, Jr. and Lawrence P.Kessler ABSTRACT: Antivibration tube spacer structure for supportinglyspacing adjacent tubes of a shell and tube heat exchanger in order toprevent damage to the tubes caused by flow-induced or other mechanicallyinduced vibration. The spacer structure comprises elongated, thin platemembers disposed between adjacent tube layers thus to provide engagementat two opposed points on the tubes. Struck out tab projections extendingnormally from the plate are arranged to engage the tubes on opposite,longitudinallyspaced points that are displaced by 90 from the points ofplate engagement.

PATENTEUAPRZDIBYI 3575236 SHEET 1 BF 6 INVENTOR NICHOLAS D. ROMANOSATTORNEY PATENTED APRZO I97! 3; 575, 236

' SHEET 2 0F 6 FIG. 2

lNVENTOR NICHOLAS D. ROMANQS BY 1 ATTORNEY PATENTED M20197: 3,575,236

SHEET 3 OF 6 noo & m

F/G 6 INVENTOR -5 NICHOLAS D. ROMANOS ATTORNEY PATENTED APRZO mm 8575236 sum u or 6 OZ l0 FIG: FIG 7 INVENTOR NICHOLAS D. ROMANOS BY \iewATTORNEY PATEN-TIEU mom 3575236 SHEET 5 UF FIG. 2! FIG. 22

INVENTOR NICHOLAS D. ROMANOS ATTORNEY PATENTEU M20 m1 SHEET 8 OF 6INVENTOR NICHOLAS D. ROMANOS ATTORNEY FORMED PLATE TUBE SPACERSTRUQTURIE BACKGROUND OF THE INVENTION During recent years shellandtube-type heat exchangers have been developed to provide a highlyefficient means for generating vapor. In this type of heat exchanger aheating medium, such as high temperature water, vapor, petroleum, orgas, among others, is passed through the tubes and gives up a portion ofits heat to a vaporizable liquid that is circulated through the chamberabout the tubes to exit the shell as saturated or superheated vapor.Such vapor generators provide a great amount of heating surface byemploying a large number of small diameter tubes disposed in a tubebundle that substantially fills the vapor generating chamber formed bythe enclosing shell.

Vapor generators of this type commonly employ tube bundles formed oflayers of U-shaped tubes, the ends of whose legs are secured to a tubesheet disposed at one end of the shell while the nexus portion of thetubes connecting the legs is disposed at the opposite end of the shell.Because such vapor generators, especially those of high capacity, are ofconsiderable axial length, the tubes that comprise the tube bundle arerelatively long, thereby rendering them highly susceptible to flowand/or other mechanically induced vibrations. Such vibration isespecially pronounced in the area of the nexus portion of the tubeswhich is the furthest removed from the points of attachment of the tubeends to the tube sheet.

In order to prevent the deleterious effects of vibration, such as damageto the tubes or other component parts of the generator, it is necessarythat means be provided to support the tubes against vibration. The tubespacer means that is ultimately employed should satisfy severalcriteria. It should properly space andsecure tubes relative to eachother. It should permit relative movement between the tubes and theshell in order to accommodate differential thermal expansion. It shouldnot impair heat transfer between the heating medium and the liquid beingvaporized. It should not substantially increase the pressure drop on thevaporizable fluid passing through the shell. And additionally, the tubesupport means cannot be so complex in design or expensive in fabricationor assembly as to render it economically unattractive.

Tube spacer structures that tend to satisfy the above criteria areembodied in U.S. Pat. applications Ser. Nos. 785,914 to Romanos, filedDec. 23, 1968 now U.S. Pat. Ser. No. 3,503,440, granted Mar. 3I, 1970,and 791,844 to Hill, filed Dec. I3, 1968 now U.S. Pat. Ser. No.3,545,537 granted Dec. 8, 1970, both of which applications are assignedto the assignee of the present application. While these earlier tubespacer structures have been found to give adequate service, theynonetheless suffer from certain manifest disadvantages. The structuredescribed in Pat. application Ser. No. 791,844 is relatively expensiveto fabricate due to the large number of component parts that requiremachining steps. It further employs members having a greater amount ofbulk, thus increasing the weight of the unit and the degree of flowrestriction encountered by the fluid flowing in the region of the tubespacer structures. The arrangement of U.S. Pat. application Ser. No.785,914, on the other hand, while overcoming some of the inadequacies ofthe former apparatus has the disadvantage of requiring a greater amountof spacing between adjacent tubes to accommodate the tube spacerstructure. This deficiency obviously reduces the amount of heat exchangesurface that can be housed within a vessel of given volume.

It is tot he improvement of such tube spacer structures, therefore, thatthe present invention is directed.

SUMMARY OF THE INVENTION By means of the present invention there isprovided tube spacer structure especially adapted for spacedlysupporting inverted U-tubes that comprise the tube bundle of shell andtube type vapor generators, or the like. According to one aspect of theinvention, the tube spacer between the laterally spaced, verticallyextending leg portions of the U-tubes. According to another aspect, thestructure is arranged to provide both lateral and vertical spacingbetween the horizontally extending nexus portions of the U-tubes.

In general terms, the .tube spacer structures of the present inventioncomprises a plurality of elongated, generally flat plate membersdisposed between adjacent layers of tubes that comprises a tube bundlehoused within a heat exchange vessel. The plate members of each tubespacer structure are aligned along a plane that intersects the planes ofthe tube layers and are mutually secured in a manner which, in one case,permits movement of the spacer structure with respect to the vesselshell under inducement by thermal expansion or contraction of the tubes,and in another case, prevents movement with respect to the shell inwhich case the tubes are allowed to undergo sliding movement withrespect to the plate members.

Each of'the plate members is provided with laterally spaced rows oflongitudinally spaced, struck out tab projections. The tab projectionsare staggeredly arranged in pairs with each pair thereof providinglaterally spaced, opposed bearing surfaces for supportingly engagingopposite sides of a tube of the adjacent tube layer, thus to engage thetube in one plane of support. Tube engagement in another plane ofsupport is provided by the bearing relation existing between the tubesof the tubes of the respective tube layers and the opposed flat surfacesof the plate members.

By reason of the herein disclosed tube spacer construction, therefore,all of the above-mentioned design criteria are satisfied. The tubespacer structure of the invention embodies a simple design that isinexpensive to fabricate. It provides means for spacingly supporting thetubes of a tube bundle in a manner that prevents any side-to-sidemovement of the tubes relative to one another while at the same timepermitting thermally induced relative movement between the tubes and theenclosing pressure shell. Ample fluid flow area is provided through thestructure such that only an insignificant impedance to flow withresulting pressure drop is developed. Additionally, because of the noveltube support arrangement cross flow of vaporizable fluid with respect tothe tubes in the region of the tube support structure can occur therebyproducing unimpaired heat transfer between the heating fluid conductedthrough the tubes and the vaporizable fluid.

In addition to the above-cited beneficial characteristics of the noveltube spacer structure of the present invention, another importantadvantage derived therefrom relates to the ease of assembly of tubebundles within pressure shells that is attendant to its use. Tubespacers employed in heat exchangers of the prior art involved solidplates drilled to permit passage of the tubes or, alternatively, anassembly of intersecting struts commonly referred to as egg cratesupports. These structures, according to the prevailing practice, wereassembled in the shell prior to inserting the tubes. Thereafter, thetubes were assembled in the shell by carefully passing each tube endthrough the openings in the respective tube spacers and finallyattaching the tube ends to the tube sheet. Obviously, a great amount ofprecision was required in fabricating and aligning the tube spacers inorder to permit proper installation of the tubes. Tube spacer structureaccording to the present invention obviates the need for such closefabrication and alignment tolerances. The plate members that comprisethe present structure can simply be arranged as each of the tube layersare assembled within the shell and subsequently affixed together and tothe shell thus significantly reducing the time, efiort and expenseheretofore attendant to the fabrication of the spacers and installationof the tubes.

DESCRIPTION OF THE DRAWINGS FIG. 2 is a vertical section in enlargeddetail of the upper portion of the tube bundle in the vapor generator ofFIG. I;

FIG. 3 is a section taken along line 3-3 of FIG. 2;

FIG. 4 is a view taken along line 4-4 of FIG. 3;

FIG. 5 is a view illustrating one form of tube spacer employed in thepresent invention;

FIG. 6 is a view illustrating another form of tube spacer employed inthe present invention;

FIGS. 7 through 10 are views illustrating plate members comprising oneform of tube spacer structure according to the present invention;

FIGS. I] through 13 are views illustrating plate members comprisinganother form of tube spacer structure according to the presentinvention;

FIG. 14 is an enlarged detail view of the means for securing theassembled ends of the plated of FIGS. 1 I through 13;

FIG. 15 is a view taken along line I5l5 of FIG. I4;

FIG. 16 is a view similar to FIG. 15 illustrating the elements ingreater detail;

FIGS. 17 and 18 are views of one form of attachment clip employed in theinvention;

FIGS. 19 and 20 are views of another form of attachment clip employed inthe invention; and

FIGS. 21 through 23 are views illustrating plate members comprising yetanother fonn of tube spacer structure according to the presentinvention,

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. I of the drawings,there is shown a shelland tubetype vapor generator 10 incorporating tubesupport structure constructed according to the present invention. Thevapor generator 10 comprises a vertically elongated pressure vesseldefined by a lower cylindrical shell 12 and a larger diameter. uppercylindrical shell 14 integrally connected with the lower shell by meansof a frustoconical transition member I6. The ends of the vessel areclosed, at the bottom by means of hemispherically formed closure head 18and at the top by a dome-shaped cover 20 containing a vapor outletnozzle 22. The interior of the pressure vessel contains baffle platemembers 24, 26, and 28 that cooperate with the wall of the shells toform an inner vapor generation chamber 30 and an outer, annulardowncomer passage 32. At the lower end of the lower shell I2, andintermediate it and closure head 18, is disposed a tube sheet 34 thatextends transversely of the axis of the vessel and connects with thewall of the shell. The tube sheet 34 contains a plurality of tubeopenings adapted to fixedly receive the ends of U-shaped heat exchangetubes 38 that form a longitudinally extending tube bundle 40substantially filling the lower region of the vapor generation chamber30. The tube openings extend through the tube sheet 34 to place thetubes 38 in fluid communication with a heating fluid chamber thatoccupies that region of the vessel enclosed between the closure head 18and the tube sheet 34 and which is divided into inlet and outletportions 44 and 46, respectively, by means of a diametral plate 48. Thetubes 38 of the tube bundle 40 are arranged such that their oppositeends communicate with one of the respective portions, 44 or 46, of theheating fluid chamber for the through-flow of heating fluid through thetubes. The heating fluid chamber is, in turn, connected to a source ofheating fluid (not shown) by means of inlet and outlet nozzles 50 and52, respectively, that communicate with the respective chamber portions44 and 46 and thereby effect circulation of heating fluid through thetubes.

Feedwater is supplied to the unit through an inlet noule 54 that isshown penetrating the upper shell 14. A ring header 56 connects with thenozzle 54 and serves to distribute feedwater passed through the nozzleabout the circumference of the downcomer passage 32 discharging it intothe passage by means of downwardly-directed discharge ports 58 that arecircumferentially spacedly disposed about the lower surface of theheader. Flow of the feedwater from the downcomer passage 32 into thevapor generation chamber 30 is effected by the spaced relationship thatexists between the lower end of the baffle plate 24 and the uppersurface of the tube sheet 34. Within the vapor generation chamber 30 thefeedwater is caused to flow in heat exchange relation with the tubes 38where heat is extracted from the heating fluid circulated therethroughto cause some of the feedwater to be transformed into vapor. Theso-created vapor-liquid mixture flows to the upper region of the vaporgeneration chamber 30 which is formed as a mixture collection chamber 60as defined by the cooperation between the baffle plates 26 and 28. Formthe mixture collection chamber 60 the flowing mixture is passed tovapor-liquid separator apparatus, a multiplicity of such separatorsindicated as 62 being mounted upon baffle plate 28 and communicatingwith the chamber 60 by means of openings 63 provided in the plate. Theseparators 62 may be of any well-known construction, those shown beingof the centrifugal type, and are arranged to discharge separated liquiddownwardly upon the baffle plate 28 from whence it is returned to thedowncomer passage 32 to be mixed with the incoming feedwater andrecirculated through the unit. The separated vapor, on the other hand,is discharged from the separators in the upward direction and passesthrough appropriate contact drying apparatus 64, from whence it isdischarged out the vapor outlet nozzle 22 and conducted to a point ofuse.

As is common in vapor generators of the disclosed type, the

U-tubes that comprise the tube bundle 40 each include a pair ofstraight, vertically extending leg portions 66 interconnected by ahorizontally extending nexus portion 68. In the tube bundle 40 of theunit disclosed herein, the great majority of the tubes 38 have nexusportions that are generally arcuate in shape. All of the tubes 38 aresmall diameter, thin-walled tubes that are arranged, as shown in FIG. 2,in closely spaced layers with each layer containing a plurality ofparallel tubes. In order to provide maximum heat transfer effectiveness,the tube layers of the present arrangement are disposed such that thetubes therein have their centers located on a triangular pitch. Sucharrangement places the tubes of each tube layer in alignment with spacesbetween the tubes of the adjacent layer, thereby to expose a greateramount of heating surface to the flowing vaporizable fluid.

Because the tubes 38 are small diameter, thin-walled members and becausethe distance between the tube sheet 34 and the top of the tube bundle 40is extensive, means must be provided for spacedly supporting the tubesalong their entire length in order to protect them against damage causedby vibration. Such structure is also required in order to impartsufficient rigidity to the tubes to permit them to maintain theirmutually spaced relationship in the tube bundle. Tube spacer structureadapted to perform these functions and constructed according to thepresent invention are illustrated in FIGS. 1 and 2 of the drawing asbeing of three generally forms. The first form, indicated generally as70, is a vertically elongated arrangement disposed in the upper regionof the tube bundle 40 and adapted to space the horizontally extendingnexus portions 68 of the U-tubes. The second form, indicated as 72, isgenerally similar in regard to its tube support structural configurationto the arrangement 70. Apparatus constructed according to this form ofthe invention however are vertically spaced throughout the height of thetube bundle and comprise horizontally extending members that serve tospace the leg portions 66 of the tubes 38. The third form of apparatus,indicated as 74, provides lateral spacing between adjacent tube layersin that region of the tube bundle 40 that cannot accommodate either ofthe structures 70 or 72 due to the proximity of the bends between theleg and nexus portions of the tubes. This latter form of the inventionis comprised of obliquely arranged members disposed adjacent the tubebends and intermediate the tube spacer apparatus 70 and 72.

The tube spacer structure 70 of the present invention is described withparticular reference to FIGS. 2 through 9 of the drawing. As shown inFIG. 2, the tube spacer structure that comprises this form of theinvention is embodied in two substantially similar arrangements,indicated in the FlG. as 78a and 70b. Tube spacer structure 70a isdisposed in the center of the upper region of the tube bundle 40 andstructure 78b is outwardly spaced from the structure 70a on both sidesthereof. The structures 70a and 70b are substantially similar inconstruction details, differing only as to the means employed to securethe lower end of the plate members that comprise the structures ashereinafter set forth. On view of the similarity that exists between thestructures 70a and 70b, the description that follows, while beingparticularly directed toward the arrangement 700, will apply equally toarrangement 70b except wherein indicated otherwise.

Tube spacer structure 70a comprises a plurality of elongated, verticallyextending, flat members 78 that are interposed between each of theadjacent layers of tubes 38 that comprise the tube bundle 40. The platemembers 78 are disposed in an aligned row that traverses the full widthof the upper region of the tube bundle and extends perpendicularly tothe axis of the nexus 68 of the tubes. Each plate member 78 is comprisedof two principal portions, a tube supporting portion 80 that occupiesthat portion of the plate member that is intersected by straight nexusportions of the tubes 38 in the adjacent tube layer and a subtendingextension portion 82 that traverses the arcuately formed bend portionsof the U-tubes. At their upper ends the plate members are provided withsubstantially centrally disposed tongue extensions 84 that are formed ofreduced width'for reception in structure members 86 as hereinafterdescribed.

As best shown in FlGS. 7 and 9 the tube supporting portion 80 of theplate members 78 contains a pair of parallel rows of generally E-shapedopenings 88 that are arranged in staggered relation on opposite sides ofthe longitudinal axis of the plate. The openings 88 are formed bystamping or otherwise removing material from the plate in the shape ofan E thereby providing an opening that includes a pair of tabs 80' and90". The tabs 90 and 90" are of unequal length with the innermost tab98' in each set being longer than the outermost tabs 90" by an amountapproximately equal the space between adjacent tubes 38 in each tubelayer. As best shown in FIG. 8, the tabs 90 are struck out from theplane of the plate members 78 to a position substantially normalthereto, thus defining projections adapted to engage the surface of thetubes.

When the plate members 78 are assembled between adjacent tube layers ofthe tube bundle 40 each tube 38 will be engaged by opposing faces of apair of tab projections 90' and 98", each being associated withalternate openings 88. For example, as shown in FIG. 7, a typical tube38 is vertically restrained on its underside by the upper surface of thetab projection 90' associated with an opening 88 in the row to the leftof the plate axis and on the other side by the under surface of the tabprojection 90" associated with the alternate opening 88 in the oppositerow. The remaining tubes 38 are similarly restrained by a tab projection90' on one side of the axis of the plate member 78 and a tab projection90" on the other side.

By means of this arrangement each tube 38 is engaged by tab projectionsat axially spaced points along the tube surface thereby providing ampleflow area for fluid to pass vertically along serpentine flow pathsthrough the region occupied by the tube spacer structure.

in the preferred embodiment of the invention the length of the projectedtabs 90' and 90" is approximately equal to the diameter of the tubebeing supported such as to locate the end edges of the respective tabsin longitudinal alignment and,

p when assembled, in abutment with the facing surface of the adjacentplate member. By so forming the tabs, means are provided to stiffen themembers along their length.

The subtending extension portion of the plate members 78 that comprisethe tube spacer structure 70a.is indicated as 82a in FIG. 7 and providesmeans for anchoring each plate member at its lower end. It comprises! animperforate that area of each tube layer that is occupied by tube bendsas shown in H0. 2. At its lower end, the extension portion 820 isprovided with an enlarged diameter aperture 92 for attaching the platemember to a connector rod 94 that extends through a diametrallyextensive area 96 of the tube bundle that is void of tubes. A second setof apertures 98 of smaller diameter than the aperture 92 are provided toaccommodate dowels 99 for attaching the plate members to spacer plats100 shown in FIG. 5 The spacer plates 100 are provided withthrough-openings 101 and 103 to accommodate the connector rod 94 and Idowels 99 and are formed of a thickness that is approximately equal tothe diameter of the tubes in order to maintain the proper spacing of theplate members at their lower end.

The extension portions indicated as 82b of the plate member 78 thatcomprises the tube spacer structure 70b are provided at their lower endswith a formed U-shaped clip 103 adapted to engage the verticallyextending leg portions 66 of a tube in the adjacent tube layer, thus tosecure the lower ends of the plate members that comprise this form ofthe arrangement.

The upper ends of the tube spacer structures 70a and 70b are secured tothe baffle plate 24 by attachment to structural members 86 that overliethe upper end of tube bundle 40 and which connect at their opposite endsto the baffle plate. As shown in FIG. 3 the structural members comprisea flange 106 and a depending web 108, the latter being formed on itslower edge as an arc of a circle to conform generally to the shape ofthe upper end of tube bundle 40. The upper ends of the plate members 78that comprise the tube spacer structures are secured to the structuralmembers 86 by means of tongue extensions 84 disposed at the upper end ofeach of the plate members and which are adapted to be weldedly attachedto the respective structural members. Attachment is effected byarranging the tongue extensions 84 between pairs of oppositely spacedretainer plates 104 that are spacedly connected to the web 108 by meansof opposed arcuate spaced plates H0 and welding the tongue extensions tothe retainer plates.

in order that thermally-induced vertical movement between the tubesupport structures 70a and 70b can occur connection of the ends of thestructural members 86 to the shell 24 is effected by means of a slidableconnector, indicated as 112 in FIG. 3. Moreover, in the case of tubespacer structure 70a, the opposite ends of the arcuate spacer platesattach a depending support plate 114 having an opening 115 adjacent itslower end for reception of the respective ends of connector rod 94.

By means of this embodiment of the invention, therefore, there isprovided a simple, inexpensive tube spacer arrangement that is effectiveto'spacingly support the nexus portions 68 of tube 38 in the upperregion of the tube bundle 40. Because the tubes 38 of each tube layerare supported on their opposite lateral sides by the opposed surfaces ofadjacent plate members 78 and on their top and bottom sides by opposingsurfaces on tab projections 90 and 90" vibrationinduced motion in thetubes is prevented. Flow of vaporizable fluid across the tubes 38 in theregion occupied by the structures 70a and 70b will not be adverselyimpeded due to the flow space provided through the structures by thelateral spacing between the tab projections 90' and 90" supporting eachtube.

in the second form of the invention, indicated as 72 in FlGS. 1 and 2,tube spacer structures are employed for laterally spacing thevertically-extending leg portions 66 of the U-tubes 38 at spacedintervals along their length. With particular reference to H68. 11through 13, the tube spacer structures 72 each comprise a plurality ofhorizontally disposed plate members that are provided with the sameoppositely spaced rows of generally E-shaped openings 88 and struck-outtab projections 90 and 90" as contained in the plate members '78 of theearlier described embodiment indicated as 70. As best shown in F165. 2and 15, the plate members 120 are extension of the body of the platemember extending across 75 disposed between adjacent layers of tubes andextend from the outer periphery of the tube bundle 40 substantially tothe middle thereof. At their outer ends the plate members are providedwith a rectilinear recess 122 for attachment to an annular band or ring124 that encircles the tube bundle and is plug welded as at 125 orotherwise fixedly attached to the downcomer baffle 24. The inner ends ofthe plate members 120 are provided with a semicircular recess 126 inorder to adapt the ends for connection to spacer plates 127 (FIG. 6)that are mounted on a connector rod 128 that extends through the void 96that defines the middle of the tube bundle. The connector rod 128 isspaced below the connector rod 94 and is attached as by means of weldingat its opposite ends to the annular band 124 that surrounds thestructure.

The spacer plates 127 as shown in FIG. 6 are provided with an enlargedcentral aperture 132 to accommodate reception of the plates on the rod96. The spacer plates 127 also contain two pair of oppositely spacedsmall diameter apertures 134 that are adapted to receive dowels whichextend through accommodating apertures 136 located adjacent the innerend of the plate member so as to effect attachment of the plate memberto the spacer plates.

In order to maintain the spaced relation between the plate members 120at their outer ends, connection of these ends of the plate members tothe annular ring 124 is achieved by threadedly connecting the respectivemembers to attachment clips 138. The clips 138 are U-shaped in sectionand have leg portions 140 of varying lengths in order that the clip bend142 in most cases can abut the outermost tube in the tube layer with thelegs weldedly engaging the annular ring 124. To facilitate engagement ofthe leg portions 140 with the annular band 124, the former is providedwith a rectilinear recess 143 that conforms generally to the recesses122 in the plate members 120. Each clip 138 is provided with upper andlower sets of threaded and unthreaded apertures for reception ofthreaded connector 146 that serve to connect the plate members 120 insandwiched relation between adjacent clips. The apertures in each setconsist of a threaded aperture 144 to receive the threaded shank ofconnector 146, and unthreaded aperture 148 to permit passage of theshank, and a somewhat enlarged diameter unthreaded aperture 150 topermit access to the connector by an operating tool. The threadedaperture 144 and enlarged unthreaded aperture 150 are in one leg of theclip and the remaining unthreaded aperture 148 is located in the otherleg in alignment with the aperture 150.

Due to the crowded condition of the region of the unit in which theattachment clips are located, it is necessary to employ clips havingalternating aperture arrangements in their legs in order to accommodatethe connectors 146. The two forms of attachment clips are illustrated inFIGS. 17 and 18 and 19 and 20. In the attachment clip 138 illustrated inFIGS. 16 and 17, the threaded aperture 144 is located closest the clipbend with the other apertures 148 and 150 being remote therefrom, whilein the arrangement of FIGS. 18 and 19 the positions of these aperturesare reversed.

When the tube spacer structures 72 are assembled in the tube bundle 40the leg portions 66 of each tube 38 in the respective tube layers areprevented from moving in relation to the tubes of the adjacent tubelayers by the interposition of the plate members 120. Likewise relativemovement between tubes 38 within the respective tube layers is preventedby the engagement of the tubes by projected tabs 90' and 90" in a mannersimilar to that of the embodiment indicated as 70. Thermally inducedrelative movement of the legs 66 of tubes 38 is permitted in thisembodiment of the invention by the relative vertical sliding motion thatis permitted to exist between the tube legs and the plate members 120.

A third embodiment of the invention is shown in detail in FIGS. 21through 23 of the drawing. This embodiment, indicated generally as 74 inFIGS. 1 and 2, adopts the concept of the invention in tube spacerapparatus capable of being utilized in that region of the tube bundle 40adjacent the tube bends that connect the leg portions 66 and nexusportions 68 and that can accommodate neither of the previously describedstructures or 72. The tube spacer structures 74, six of which are shownin FIG. 1 as being employed in the described embodiment, each comprise aplurality of aligned, obliquely set, thin, flat plate members 152arranged in the spaces between each tube layer. Along the longitudinalside edges of each plate member 152, projected tabs 154 are struck outfrom the body thereof and offset normally thereto to form tube spacerelements in a fashion not substantially unlike that of the tabs in thepreviously described structures. In fabricating the tabs 154 a series oflateral slots 156 are first cut into the plate members 152 atlongitudinally spaced points along the length of both side edgesthereof. The slots 156 are angularly disposed with respect to the sideedges to an extent that presents them in generally horizontaldisposition when the members 152 are assembled in the tube bundle. Theplate material between each of the slots 156 is then offset to aposition normal to the surface of the plate members and along lines atright angles to the edges of the slots thus to form the tube-engagingtabs 154.

As best shown in FIG. 21, the offset tabs 154 along opposite side edgesare arranged such that each tube 38 in the respective adjacent tubelayer is engaged on opposite sides at axially spaced points byalternately spaced tabs. In this way, each of the tabs 38 is engaged ontwo oppositely spaced sides in one plane of support by the tabs 154. Inthe other plane of support, which is offset by 90 from the first plane,each tube will be engaged on opposite sides by the surface of theadjacent plate members 152.

As is evident from examination of FIG. 2, two slightly difi'erent formsof tube spacer structures 74 are employed in the described vaporgenerator arrangement. The structures 74 located nearest the tube bendshave their lower end edges attached to the spacer plates that space theplate members 78 of the central vertically extending tube spacingstructure 70. Attachment of the plate members 152 to the plates 100 iseffected by dowel connectors for which apertures 158 are providedadjacent the lower ends of the members 152. At the opposite end, eachplate member 152 is provided with a rectilinear recess 160 toaccommodate attachment of plate members to an annular band 162 thatencircles the tube bundle thereby securing the upper ends of the platemembers.

In order to permit thermally induced movement of the tubes 38, the band162, in the described embodiment, is not attached to the inner surfaceof the downcomer baffle 24, but instead is arranged for sliding contactwith the inner surface of that baffle. In this way these tube spacerstructures are pennitted to undergo vertical movement with the tubes 38between the latters expanded and contracted position.

The plate members 152 of the remaining tube spacer structures indicatedas 74 in FIG. 2 have the same general configuration as those of thestructures illustrated in FIG. 20 with the exception that their lowerends are provided with a simple straight edge 164 (FIG. 2) which isadapted to rest on the upper side edge of the adjacent plate memberdisposed in the uppermost tube spacer structure 72. It should also benoted that the annular bands 162 that engage the upper ends of the platemembers 154 of these lower tube structures 74 are fixedly secured at theinner surface of the downcomer baffle 24 by means of a plug weld 164 orthe like. With the plate members 152 and these lower tube spacerstructures 74 being fixedly secured with respect to the shell, theexpansion and contraction of the tubes is accommodated throughout thestructures by the relative sliding movement that is permitted to occurbetween the tubes 38 and the struck out tabs 154 on these members.

There has thus been described a tube spacer structure that is effectiveto supportingly space the tubes of a tube bundle against the harmfuleffects of vibration. Tube spacer structure according to the invention,as compared with spacers of the prior art, is much simpler in design,less costly to fabricate and install and provides a greater amount offluid flow area through the structure thus to reduce the amount ofpressure loss normally expected from the presence of tube spacers.

it will be understood that various changes in the details, materials,and arrangements of parts which have been herein described andillustrated in order to explain the nature of the invention may be madeby those skilled in the art within the principle and scope of theinvention as expressed in the appended claims.

lclaim:

1. in a heat exchanger having a tube bundle, the improvement comprisingbetween adjacent tubes in a tube bundle including a plurality of spacedlayers of aligned, mutually spaced, parallel tubes, said tube spacerstructure comprising:

a. a plurality of elongated, flat plate members, each being disposedbetween the respective tube layers and alignedly arranged in a row thatintersects the planes of said tube layers;

b. said plate members being each provided with a plurality of tabprojections extending from the surface thereof, said ,tab projectionsbeing arranged in rows that are oppositely spaced from, and extendsubstantially parallel to, the longitudinal axes of the respective platemembers;

c. the tab projections on each of said plate members being arranged inpairs for engaging said tubes, each of said pairs consisting of twooppositely facing tab projections longitudinally spaced from one anotherby a distance corresponding substantially to the diameter of the engagedtube, one of the tab projections in each pair emanating from one of saidrows and the other of said tab projections emanating from the other rowwhereby said tubes are each engaged at opposite, axially spaced points;and

d. means for retaining said plate members in mutually fixed relation.

2. Tube spacer structure as recited in claim 1 wherein said flat platemembers are disposed with their opposite faces in bearing relation withthe tubes of adjacent tube layers.

3. Tube spacer structure as recited in claim 2 wherein the bearingsurfaces presented by said tab projections are in planes substantiallynormal to said plate members.

4. Tube spacer structure as recited in claim 3 wherein said platemembers are angularly disposed with respect to the axes of the engagedtubes.

5. Tube spacer structure as recited in claim 43 wherein said tabprojections are provided with their free end edges in abutting relationto the adjacent plate member.

6. Tube spacer structure as recited in claim 4 wherein the bearingsurfaces presented by said tab projections are in planes substantiallynormal to the longitudinal axes of the respective plate members.

7. Tube spacer structure as recited in claim t wherein the bearingsurfaces presented by said tab projections are in planes disposedobliquely with respect to the longitudinal axes of the respective platemembers.

8. Tube spacer structure as recited in claim 6 wherein said tabprojections are arranged in groups of two, said groups being disposed inoppositely spaced rows on alternate spacing and the tab projections ineach group being disposed in sideby-side relation with the bearingsurfaces presented thereby being longitudinally spaced from one anotherby an amount substantially equal to the desired spacing between thetubes in the adjacent tube layers.

9. Tube spacer structure as recited in claim 8 wherein said groups oftab projections are defined by stamped, generally E- shaped openings 10.Tube spacer structure as recited in claim 7 wherein the longitudinalside edges of said plate members are formed with tab projections spacedtherealong, each of said tab projections on each side edge having acomplementary tab projection on the other side edge to define a pair,and the bearing surfaces presented by each of said pairs of tabprojections being in opposing, longitudinally spaced relation to oneanother and mutually laterally spaced by an amount equal to the diameterof the tube to be engaged thereby.

11. A heat exchanger for the indirect transfer of heat from one fluidmedium to another comprising, in combination:

a. an elongated pressure shell;

b. a tube sheet transversely arranged within said shell and dividing thesame into a first chamber and a second chamber;

. a tube bundle including a plurality of spaced layers of aligned,mutually-spaced, parallel tubes disposed within said first chamber withthe ends of said tubes connected to said tube sheet and in fluidcommunication with said second chamber;

d. means including said second chamber for circulating one of saidfluids through said tubes;

e. means for supplying the other of said fluids to said first chamber toflow over said bundle of tubes; and

tube spacer structure means for maintaining the spacing between adjacenttubes in said tube bundle, including:

i. a plurality of elongated, flat plate members, each being disposedbetween the respective tube layers and alignedly arranged in a row thatintersects the planes of said tube layers;

ii. said plate members being each provided with a plurality of tabprojections extending from the surface thereof, said tab projectionsbeing arranged in rows that are oppositely spaced from, and extendsubstantially parallel to, the longitudinal axes of the respective platemembers;

iii. the tab projections on each of said plate members being arranged inpairs for engaging said tubes, each of said pairs consisting of twooppositely facing tab projections longitudinally spaced from one anotherby a distance corresponding substantially to the diameter of the engagedtube, one of the tab projections in each pair emanating from one of saidrows and the other of said tab projections emanating from the other rowwhereby said tubes are each engaged at opposite, axially spaced points;and

iv. means for retaining said plate members in mutually fixed relation.

12. The combination as recited in claim 11 including tubes in said tubebundle extending substantially parallel to the axis of said pressureshell and a plurality of tube spacer structures axially spacedthroughout the length of said tubes, each of said tube spacer structuresincluding plate members extending transversely of the axis of saidpressure shell and having tab projections disposed in two oppositelyspaced rows along the length of said plate members, said tab projectionsbeing substantially normally offset from the surface of said platemembers and presenting tube bearing surfaces that are angularly disposedwith respect to the longitudinal edges of said plate members, the platemembers of the respective tube spacer structures being fixedly securedwith respect to said pressure shell and the tab projections engagingsaid tubes for sliding movement therebetween.

13. The combination as recited in claim 12 wherein said tube spacerstructures each comprise horizontally elongated plate members, each ofsaid plate members having tab projections arranged in groups of two,said groups being disposed in oppositely spaced rows on alternatelongitudinal spacing and the tab projections in each group beingdisposed in side-by-side relation, the bearing surfaces presented by therespective pairs of tab projections being mutually vertically spaced andlaterally opposed to engage said tubes on opposite sides thereof, saidplate members extending beyond the outer periphery of said tube bundle,an annular band retaining the extended ends of said plate members, andmeans for fixedly securing said annular band with respect to saidpressure shell.

14. The combination as recited in claim 13 wherein said groups of tabprojections are each defined by a stamped,

generally E-shaped opening.

15. The combination as recited in claim 13 wherein the plate members ofsaid tube spacer structures have their inner ends terminatingsubstantially midway through said tube bundie, a diametrally extensiveconnector rod extending through said tube bundle transversely of theends of said plate members, means for securing the inner ends of saidplate members to said connector rod, and means for fixedly securing theends of said connector rod with respect to said pressure shell.

16. The combination as recited in claim 12 wherein said tube spacerstructures each comprise elongated plate members, obliquely disposedwith respect to the axis of said pressure vessel, the longitudinal sideedges of said plate members being formed with tab projections spacedtherealong, each of said tab projections on each side edge having acomplementary tab projection on the other side edge to define a pair,the bearing surfaces presented by each of said pairs of tab projectionsbeing mutually vertically spaced and laterally opposed to engage saidtubes on opposite sides thereof, said plate members extending beyond theouter periphery of said tube bundle, and an arcuate band surroundingsaid tube bundle and retaining the extended ends of said plate membersin mutually fixed relation.

17. The combination as recited in claim 16 including means for fixedlysecuring said arcuate band with respect to said pressure shell.

18. The combination as recited in claim 16 wherein said arcuate band isaxially movable with respect to said pressure shell.

19. The combination as recited in claim 18 wherein the plate members ofsaid tube spacer structures have their inner ends terminatingsubstantially midway through said tube bundle, a diametrally extensiveconnector rod extending through said tube bundle transversely of theends of said plate members, means for securing the inner ends of saidplate members to said connector rod, and means for vertically movingsaid connector rod with respect to the axis of said pressure shell. I

20. The combination as recited in claim 11 wherein the tubes of saidtube bundle are generally U-shaped having the nexus portionsinterconnecting the legs of said tubes disposed uppermost in said tubebundle and wherein said tube spacer structures engage the nexus portionsof said U-tubes and each comprise vertically extending plate membershaving the tab projection bearing surfaces of each of said pairsengaging the nexus portion of said tubes at axially spaced pointstherealong.

21. The combination as recited in claim 21 wherein said tab projectionsare arranged in groups of two, disposed in side-byside relation, saidgroups being disposed in oppositely spaced rows on alternatelongitudinal spacing, the bearing surfaces presented by the respectivepairs of tab projections being mutually laterally spaced and verticallyopposed to engage the nexus portion of the tubes on opposite sidesthereof.

22. The combination as recited in claim 21 wherein said groups of tabprojections are each defined by a stamped, generally E'shaped opening.

23. The combination as recited in claim 21 including means disposedabove the upper end of said tube bundle for suspendedly supporting saidplate members in mutually fixed relation, said means comprising astructural member overlying the upper ends of said plate members, meansfor securing said ends of said plate members to said structural memberand means for attaching the ends of said structural member with respectto said pressure shell.

24. The combination as recited in claim 23 wherein said structuralmember attaching means provides for vertical movement of said structuralmember with respect to said pressure shell.

25. The combination as recited in claim 24 wherein the lower ends ofsaid plate members extend into said tube bundle, terminating below thelowermost of said nexus portions, and including a diametrally extensiveconnector rod extending through said tube bundle below the nexusportions of the tubes thereof, and means for securing the lower ends ofsaid plate members tosaid connector rod. I

26. The combination as recited in claim 24 wherein the lower ends ofsaid plate members are disposed adjacent the leg portions of said tubesand include clip connectors for engaging said lower ends to said legportions.

UNITED STATES PATENT OFFICE 5 CERTIFICATE OF CORRECTION t nt N 3575-226Dated April 20, 1971 Inventor) Nicholas D. Romanos It is certified thaterror appears in the above identifled patent and that said LettersPatent are hereby corrected as shown below:

Column 1, line 68, replace "tot he" with -to the--;

Column 2, line 1, after "spacer" insert -structure is so arranged as toprovide anti-vibration support spacing--;

Column 4, line 33 after "portions" insert --68--;

Column 4 line 33, after "generally" insert --straight. Those tubesindicated as 68' however that lie in the innermost tube rows may beformed, as shown, with nexus portions that are generally--;

Column 5, line 9, replace "On" with -In-;

Column 5 line 15, after "flat" insert --plate-;

Column 5, line 37, replace "80'" with -90'-;

Column 5, line lO, after "equal" insert --to--;

Column 6, line 8, replace "plats" with --plates-;

Column 6, line 16, replace "103" with --lO2--;

Column 6, line 38, replace "spaced" with -spacer-. Column 12 line 6,replace "claim 21" with claim 20 Signed and sealed this 1st day ofAugust 1972.

SEAL) Attest:

L EDWARD M.FLEITCHER,JR. ROBERT GOT'I'SCHALK Attesting OfficerCommissioner of Patents

1. In a heat exchanger having a tube bundle, the improvement comprisingbetween adjacent tubes in a tube bundle including a plurality of spacedlayers of aligned, mutually spaced, parallel tubes, said tube spacerstructure comprising: a. a plurality of elongated, flat plate members,each being disposed between the respective tube layers and alignedlyarranged in a row that intersects the planes of said tube layers; b.said plate members being each provided with a plurality of tabprojections extending from the surface thereof, said tab projectionsbeing arranged in rows that are oppositely spaced from, and extendsubstantially parallel to, the longitudinal axes of the respective platemembers; c. the tab projections on each of said plate members beingarranged in pairs for engaging said tubes, each of said pairs consistingof two oppositely facing tab projections longitudinally spaced from oneanother by a distance corresponding substantially to the diameter of theengaged tube, one of the tab projections in each pair emanating from oneof said rows and the other of said tab projections emanating from theother row whereby said tubes are each engaged at opposite, axiallyspaced points; and d. means for retaining said plate members in mutuallyfixed relation.
 2. Tube spacer structure as recited in claim 1 whereinsaid flat plate members are disposed with their opposite faces inbearing relation with the tubes of adjacent tube layers.
 3. Tube spacerstructure as recited in claim 2 wherein the bearing surfaces presentedby said tab projections are in planes substantially normal to said platemembers.
 4. Tube spacer structure as recited in claim 3 wherein saidplate members are angularly disposed with respect to the axes of theengaged tubes.
 5. Tube spacer structure as recited in claim 4 whereinsaid tab projections are provided with their free end edges in abuttingrelation to the adjacent plate member.
 6. Tube spacer structure asrecited in claim 4 wherein the bearing surfaces presented by said tabprojections are in planes substantially normal to the longitudinal axesof the respective plate members.
 7. Tube spacer structure as recited inclaim 4 wherein the bearing surfaces presented by said tab projectionsare in planes disposed obliquely with respect to the longitudinal axesof the respective plate members.
 8. Tube spacer structure as recited inclaim 6 wherein said tab projections are arranged in groups of two, saidgroups being disposed in oppositely spaced rows on alternate spacing andthe tab projections in each group being disposed in side-by-siderelation with the bearing surfaces presented thereby beinglongitudinally spaced from one another by an amount substantially equalto the desired spacing between the tubes in the adjacent tube layers. 9.Tube spacer structure as recited in claim 8 wherein said groups of tabprojections are defined by stamped, generally E-shaped openings
 10. Tubespacer structure as recited in claim 7 wherein the longitudinal sideedges of said plate members are formed with tab projections spacedtherealong, each of said tab projections on each side edge having acomplementary tab projection on the other side edge to define a pair,and the bearing surfaces presented by each of said pairs of tabprojections being in opposing, longitudinally spaced relation to oneanother and mutually laterally spaced by an amount equal to the diameterof the tube to be engaged thereby.
 11. A heat exchanger for the indirecttransfer of heat from one fluid medium to another comprising, incombination: a. an elongated pressure shell; b. a tube sheettransversely arranged within said shell and dividing the same into afirst chamber and a second chamber; c. a tube bundle including aplurality of spaced layers of aligned, mutually-spaced, parallel tubesdisposed within said first chamber with the ends of said tubes connectedto said tube sheet and in fluid communication with said second chamber;d. means including said second chamber for circulating one of saidfluids through said tubes; e. means for supplying the other of saidfluids to said first chamber to flow over said bundle of tubes; and f.tube spacer structure means for maintaining the spacing between adjacenttubes in said tube bundle, including: i. a plurality of elongated, flatplate members, each being disposed between the respective tube layersand alignedly arranged in a row that intersects tHe planes of said tubelayers; ii. said plate members being each provided with a plurality oftab projections extending from the surface thereof, said tab projectionsbeing arranged in rows that are oppositely spaced from, and extendsubstantially parallel to, the longitudinal axes of the respective platemembers; iii. the tab projections on each of said plate members beingarranged in pairs for engaging said tubes, each of said pairs consistingof two oppositely facing tab projections longitudinally spaced from oneanother by a distance corresponding substantially to the diameter of theengaged tube, one of the tab projections in each pair emanating from oneof said rows and the other of said tab projections emanating from theother row whereby said tubes are each engaged at opposite, axiallyspaced points; and iv. means for retaining said plate members inmutually fixed relation.
 12. The combination as recited in claim 11including tubes in said tube bundle extending substantially parallel tothe axis of said pressure shell and a plurality of tube spacerstructures axially spaced throughout the length of said tubes, each ofsaid tube spacer structures including plate members extendingtransversely of the axis of said pressure shell and having tabprojections disposed in two oppositely spaced rows along the length ofsaid plate members, said tab projections being substantially normallyoffset from the surface of said plate members and presenting tubebearing surfaces that are angularly disposed with respect to thelongitudinal edges of said plate members, the plate members of therespective tube spacer structures being fixedly secured with respect tosaid pressure shell and the tab projections engaging said tubes forsliding movement therebetween.
 13. The combination as recited in claim12 wherein said tube spacer structures each comprise horizontallyelongated plate members, each of said plate members having tabprojections arranged in groups of two, said groups being disposed inoppositely spaced rows on alternate longitudinal spacing and the tabprojections in each group being disposed in side-by-side relation, thebearing surfaces presented by the respective pairs of tab projectionsbeing mutually vertically spaced and laterally opposed to engage saidtubes on opposite sides thereof, said plate members extending beyond theouter periphery of said tube bundle, an annular band retaining theextended ends of said plate members, and means for fixedly securing saidannular band with respect to said pressure shell.
 14. The combination asrecited in claim 13 wherein said groups of tab projections are eachdefined by a stamped, generally E-shaped opening.
 15. The combination asrecited in claim 13 wherein the plate members of said tube spacerstructures have their inner ends terminating substantially midwaythrough said tube bundle, a diametrally extensive connector rodextending through said tube bundle transversely of the ends of saidplate members, means for securing the inner ends of said plate membersto said connector rod, and means for fixedly securing the ends of saidconnector rod with respect to said pressure shell.
 16. The combinationas recited in claim 12 wherein said tube spacer structures each compriseelongated plate members, obliquely disposed with respect to the axis ofsaid pressure vessel, the longitudinal side edges of said plate membersbeing formed with tab projections spaced therealong, each of said tabprojections on each side edge having a complementary tab projection onthe other side edge to define a pair, the bearing surfaces presented byeach of said pairs of tab projections being mutually vertically spacedand laterally opposed to engage said tubes on opposite sides thereof,said plate members extending beyond the outer periphery of said tubebundle, and an arcuate band surrounding said tube bundle and retainingthe extended ends of said plate members in mutually fixed relation. 17.The combination as recited in Claim 16 including means for fixedlysecuring said arcuate band with respect to said pressure shell.
 18. Thecombination as recited in claim 16 wherein said arcuate band is axiallymovable with respect to said pressure shell.
 19. The combination asrecited in claim 18 wherein the plate members of said tube spacerstructures have their inner ends terminating substantially midwaythrough said tube bundle, a diametrally extensive connector rodextending through said tube bundle transversely of the ends of saidplate members, means for securing the inner ends of said plate membersto said connector rod, and means for vertically moving said connectorrod with respect to the axis of said pressure shell.
 20. The combinationas recited in claim 11 wherein the tubes of said tube bundle aregenerally U-shaped having the nexus portions interconnecting the legs ofsaid tubes disposed uppermost in said tube bundle and wherein said tubespacer structures engage the nexus portions of said U-tubes and eachcomprise vertically extending plate members having the tab projectionbearing surfaces of each of said pairs engaging the nexus portion ofsaid tubes at axially spaced points therealong.
 21. The combination asrecited in claim 21 wherein said tab projections are arranged in groupsof two, disposed in side-by-side relation, said groups being disposed inoppositely spaced rows on alternate longitudinal spacing, the bearingsurfaces presented by the respective pairs of tab projections beingmutually laterally spaced and vertically opposed to engage the nexusportion of the tubes on opposite sides thereof.
 22. The combination asrecited in claim 21 wherein said groups of tab projections are eachdefined by a stamped, generally E-shaped opening.
 23. The combination asrecited in claim 21 including means disposed above the upper end of saidtube bundle for suspendedly supporting said plate members in mutuallyfixed relation, said means comprising a structural member overlying theupper ends of said plate members, means for securing said ends of saidplate members to said structural member and means for attaching the endsof said structural member with respect to said pressure shell.
 24. Thecombination as recited in claim 23 wherein said structural memberattaching means provides for vertical movement of said structural memberwith respect to said pressure shell.
 25. The combination as recited inclaim 24 wherein the lower ends of said plate members extend into saidtube bundle, terminating below the lowermost of said nexus portions, andincluding a diametrally extensive connector rod extending through saidtube bundle below the nexus portions of the tubes thereof, and means forsecuring the lower ends of said plate members to said connector rod. 26.The combination as recited in claim 24 wherein the lower ends of saidplate members are disposed adjacent the leg portions of said tubes andinclude clip connectors for engaging said lower ends to said legportions.